Vascular endothelial cell distribution and adhesion molecule expression in xanthoma

The migration of circulating monocytes into the dermis is considered to be essential for both the initiation and the progression of xanthoma. The contribution of vascular endothelial cells to the migration process is unclear.

Twenty cases of xanthelasma and six cases of tuberous xanthoma lesions were analyzed using immunohistochemical staining.

Xanthoma lesions contained up to 25-fold more von Willebrand factor-stained endothelial cells than normal skin. The prevalence of E-selectin-positive endothelial cells increased by up to threefold more in xanthoma lesions than in normal skin. In contrast, the prevalence of intercellular cell adhesion molecule-1 (ICAM-1) decreased up to 3.5-fold more in xanthoma lesions than in normal skin. In xanthoma lesions, almost all ICAM-1-positive endothelial cells co-expressed with E-selectin but many endothelial cells, which only expressed E-selectin, were also found in the lesions and the ratio of macrophages to endothelial cells was higher (10:1) than that in normal skin (5:1).

Endothelial cells proliferate and express E-selectin rather than ICAM-1 under a microenvironment in which macrophages predominate rather than endothelial cells, thereby promoting macrophage migration into xanthoma lesions.